Research On The Locomotion Charactistics Of The Jumping Behavior For The Bionic Cricket Robot

With the increasingly widespread application of robots, the working environments which the robots face are more and more complex. Therefore, the robots are required to have strong ability to move independently and adapt to different terrains. The jumping behavior of the crickets has the characteristics such as jumping fast, long distance, low energy consumption, low requirements on the ground environments, moving steadily, etc. Particularly, it is suited to the locomotion under complex, even abominable circumstances. Thus the robots designed based on the crickets must be widely used in the fields such as interplanetary exploration, military reconnaissance, and so on. In order to design and develop a kind of robots whose locomotion is in line with the real cricket jump, this thesis introduces the model of the mechanism for the bionic cricket hopping robot and carries on the research about the jumping characteristics of the cricket robot. All the work will provide theoretical basis on the design and motion control of the bionic cricket hopping robot.Firstly, the theoretical basis about the model of the mechanism for the bionic cricket hopping robot has been set up in this thesis after referring to the related documents and materials both at home and abroad, as well as considering studies on the hopping robots and bionic robots.Secondly, the model of mechanism for the bionic cricket hopping robot was established on the basis of the body configuration and locomotion of a cricket. Besides, the kinematic equations were established and the equations with respect to the positions and gestures of the robot, as well as the ones used to calculate the trajectory of the center of mass of the body during the jumping process were also mentioned, all of which allows kinematic analysis. Additionally, the differential relationship between the center of mass of the body and the joint angles of the legs, which allows velocity analysis, was established. The kinematic simulation of the robot was carried out and the results were discussed. These results are similar to the ones from biological study of the crickets, showing the feasibility of the model and the validity of the approach for kinematic analysis.Thirdly, the velocity and force manipulability measures of the cricket robot were defined through the velocity Jacobian matrix on the basis of the kinematic analysis and the properties of the robot mechanism itself. Then, the velocity and force transmissibility of the cricket robot were measured by taking the velocity and force manipulability measures as the performance index. In addition, taking the velocity and force manipulability measures as the performance index, the variation of the hind leg joint angles could be optimized based on the generalized inverse solution and the feasibility of the optimization method was verified through an example.Additionally, the dynamic equations for the bionic cricket hopping robot during the take-off stage of the stance phase were established by taking advantage of Lagrange Method and the dynamic simulation was processed on the basis of an example to gain the variation of the driving forces on the joints of the robot leg mechanism as well as their characteristics. Meanwhile, this thesis introduced a special model of the bionic cricket robot--the pseudo rigid body model, in order to optimize the joint torques of the hind legs. The torsional springs fixed on the joints of the robot mechanism could be used to mimic the flexability of the joints on the cricket legs, as well as the energy storage function of its leg muscles.Finally, the virtual prototype of the bionic cricket hopping robot was established by using ADAMS and the simulation of the movement during both takeoff stages of the stance phase and the aerial phase were processed. The motion of the center of mass of the body and the dynamic parameters of the legs were then obtained. The correctness and feasibility of the model established, along with the approaches of the kinematic and dynamic analysis were verified when comparing the simulation results with the results obtained when applying MATLAB.